Ravi Shekhar with Corbin Covault

Design and Testing of a Solid State Tertiary Detector Element and Amplification Scheme for the Pierre Auger Project

With the southern hemisphere Auger array nearing completion, it is now time to shift attention to the design of northern hemisphere array. In addition to the particle and fluorescence detectors, an additional detector is being considered. This tertiary detector would detect Cherenkov light from extremely high energy (10^18 eV and up) cosmic rays. It needs to be highly reliable and able to operate continuously for approximately twenty years without human intervention. Because of such stringent requirements, Solid State Silicon or Germanium photodetectors seem like the most likely candidate. But the sensor itself is not enough. In the case of a Silicon photodiode, the signal from an actual Cherenkov event is on the order of tens of picoamps. The noise background is usually on the order of nanoamps. It will take an exceptionally well designed filter in order to amplify the signal and cut through the noise. Various types of photodetectors will be explored and once a candidate is chosen, an amplification scheme will be designed. To this effect, testing will be done with a UV laser that simulates a Cherenkov spectrum, and possibly with computer simulations.